Piston for controlling fluids under pressure



ANGELO PETIT LE BRUN.

PISTON FOR CONTROLLING FLUIDS UNDER PRESSURE.

APPLICATION FILED 35019, 1916.

Patented Mar. 1922.

A T TUE/V575 ANGELO PETIT LE BRUN.

PISTON FOR CONTROLLING FLUiDS UNDER PRESSURE.

APPLICATION rim) DEC-19,1916.

1,409,556. Patented Mai. 14, 1922.v

2 SHEETS-SHEET 2.

BYM

UNHTED STATES.

PATENT QFFI'CE.

ANGELO PETI'J. LE mum, or raarsxrmmcn, AssIc oE 'ro comrAcmE- DEs EoEGEs ET AGIERIES DE LA MARINE E'l. DEoMEco R'r, or rams, TRANCE.

rrsroar roa con'rnormme i'mnfos UNDER PRESSURE.

Specification of Letters Patent. Patented M 14 1922.

Application filed December 19, 1916. Serial No. 137,927.

(GRANTED UNDER THE raovrsrons orrnE ACT ormaacn'a, 1921,41 sr ar. L; 1313.

To all whomit concern Be it known that I, ANGELO P 'rrr LE BRUN, a citizen of the French Republic, and

residing in Paris, France, 38 Rue de' Berri,

have invented certain new and useful Improvements in and Relating to Pistons for Controlling .Fluids Under Pressure, (for which I have filed an application in France the 31st of January, 1914, Patent 475,324,)

of which the following is a complete specification.

The present invention relates to a fluidtight movable partition or piston intended to separate ,two fluids under pressure without permitting these fluids ,to mix or lose in ressure. 7

This result is'obtained by constituting the.

partition of two elements adapted to approach each other by means of controlling members or otherwise, and compressing a fluid-tight packing interposed between the two elements, a space being provided be-j tween them in such a manner that the parts of the elements which correspond to this space, support a reaction the pressure per unit of area of surface exposed to it of which is less than that of the pressure exerted on either side of the partition as long which the fluid-tight partition is provided with a rod extending into the atmosphere,

the whole constituting the piston of a pump,

compressor or accumulator.

Referring to Figure 1, the movable iiuidtight partition comprises two elements 1, 2

arranged in a common conduit 3, in which this partition must move whilst maintaining a fluid-tight separation between its two sides. Each of the elements 1 and 2, for

filled with air under atmospheric pressure or even at a lower pressure.

The annular space existing around the' members 4 and 5 and thespace or chamber 7, is filled witha plastic or elastic material 8 such as, for example, grease, 'greasy fibres, india-I'ubber and the like.

; After mounting, the conduit 3 .is supposed to be filled on either side of the partition with fluids under pressure.

Neglecting the small pressure of the air containedin the chamber 7 the total pressure exerted on one of the elements 1 or 2, may be regarded'as beingtransmitted integrally to the plastic material 8 on an annular section obviously smaller than. that of the elements 1 and 2 because the constricted members 4 and 5 of the said elements which constitute the extreme walls of the chamber 7 support an insignificant reaction. It follows therefrom that the unitary pressure or portional to the said pressure.

The increase of pressure in the plastic material will be greater the smaller the annular section of this material owing to the widening of the chamber 7.

The pressure per unit of area of surface exposed to it of the plastic material 8 being greater than that exerted on each of the ele- 'ments 1, 2, it follows therefrom that a fluidtight separation is obtained between the chambers delimited by the elements land 2, that is to say it is impossible for the fluids placedrgn either side of the partition to mix. The pl stic material 8 may tend to escape on either side, but the constructional forms described hereinafter will illustrate the precautions taken in order to avoid this occurrence.

If the movable partition moves in the conduit 3 whilst supporting on its extreme faces the same or different pressures, the pressure per unit of area of surface exposed to it of the plastic material 8 be1ng always greater than those acting on the external faces of the elements 1, 2, the fluid-tightness will continue irrespective of the position of thlspartition. Y v

In the "constructional form of the movable partition illustrated in Figure 2, the chamber 7 is provided within one of the elements, for instance, in the. element 1 and the constricted portion 3 of the other element slldes in this chamber. The plastic material 8 cannot penetrate this chamber owing to the 1nterposition of the packing 9, for example a cupped leather, creating fluid-tlghtness between the part 5 and the element 1, so as to maintain the chamber 7 devoid of pressure. This packing bears also on the wall. of the conduit 3 so as to avoid any loss of plastic material 8 on that side of the'partition The plastic material 8 may be maintained 1n the same manner on theTSide of the element 2 or,

as illustrated, by means of a plastic or elastic packing 10 located in a recess formed in the element 2 and upon which bears the annular edge 11 of the plate 12 wh1ch maybe rendered integral with the element 2, for 1nstance, by a bayonet joint 13. A space 14 existing' between the said plate and the element 2 permits of compressing the packing 10 to a greater extent than the hi obtain fluid-tightness in a similar manner to what is effected for the plastic material 8, this compression being susceptible, however, of being produced in any suitable way.

If during the displacements of the movable partition, a leakage of the material 8 takes place on either side of the sald partition notwithstanding the provision of the "packing 9 and 10, the member 5 will penetrate the chamber 7 to a greater extent so that the pressure of the plastlc material 8 will remain greater than the pressure of the fluids acting on the elements 1, 2 and fluidtightness will be ensured for all conditions of operation as long as the pressure in the chamber 7 is somewhat less than that of the fluids in the conduit 3. As long as the elements 1 and 2 do not come into actual contact, the pressure in the chamber 7 will never be equal or approximately equal to the presaterial 8 so as to ingly shaped-recess 20 formed in the element 1, thus ensuring fluid-tightness on the same principle of over or excess pressure- Finally,Figure 4 shows the location of the two elementsl and 2 which is similar to that of the elements 2 in Figures 2 and 3. In this constructional form, however, the memher 5 is terminated by a shoulder 22 limiting the space of the elements 1 and 2. The fluid-tightness of this part is ensured by the stufling-box 23 which forms an abutment for the shoulder 22.

The arrangement of the parts may obviously be varied provided the two elements 1 and 2 effect a relative movement, which may or may not be contr olled,,in order to compensate for possible leakages of the plastic material 8, provided this substance is stored between the elements 1 and 2 in a section smaller than that of the elements, in order to obtain, in the'substance, a unitary and suitably greater pressure ensuring fluidtightness. 'A suitable filling member may be provided, .so as to permit of the introduction of the plastic material 8, even in operative position, in the case where this material is constituted by grease -or other flowing material.

This movable fluid-tight partition may be applied, for example, to hydraulic transmissionsfor motor cars or other applications as illustrated in Figure 5. 33 designates a primary hydraulic motor, operated by any engine, and connected through the medium of the conduits 27 and 34 to a secondary'hydraulic motor 35, the conduit 27, being for example, the conduit under pressure foroperation in the normal direction. The movable partition 24 is arranged in a chamber 25 closed hermetically at one end and communicating freely at its other end 26 with the conduit 27 containing liquid under pressure. A shoulder 28 preferably limits the stroke of the partition 24 in order to maintain a suitably predetermined pressure for the gas occupying the space comprised between this partition and the end of the chamber 25. The compressed gas can, however, be replaced by a spring or a group of springs. In the inoperative positionpwhen the partition 24 abuts against the shoulder 28, it preventsany leakage of gas the pressure of which is always transmitted to the plastic material.

In the case of the application of the invention to an :air accumulator as illustrated in Figure 6, the movable partition 24 which,

as in the preceding case, may have the form shown in Figures 2 to 4, is subjected in the accumulator 29 to the pressure of water or other fluid entering through the pipe 30, the chamber 31- containing compressed air or a fluid preferably elastic and under pressure, 1

or a spring.

In the constructional forms illustrated in Figures 5 and 6, the movable partition 24 avoids any mixing of the fluid forming an elastic cushion with the other fluid, liquid or gaseous, belonging to the transmission, or intended to perform any kind of work, this partition 24 being capable of movement, without interfering with its fluid-tightness, according to the various conditions of operation.

Finally, according to Figure 7 it is possible to provide this movable partition 24 with a rod 33 in order to cause it to transmit the thrust of a liquid contained in the chamber 32 or compress any liquid.

The movable fluid-tight partition according to the invention, may be utilized for separating two liquids under pressure, whether these fluids are liquid or gaseous. It,may also serve for the insulation of a single fluid under pressure in contact with one of the faces of the partition, the other face of which would then be in contact with atmospheric air by supporting directly or through the medium of a rod, a resistance equilibrating the pressure of the fluid.

The invention may be applied in all cases where use is made of compressed air or any other gas or fluid, elastic or not, under pressure, particularly when it is desired to retain a certain volume of fluid under pressure without any outlet, as is the case, for example, in shock absorbers, compressors, railway brakes, artillery brakes, shock deadeners and so on.

What I claim is 1. A piston embodying opposed spaced members and interposed plastic packing between said members, the packing being engaged by portions of the piston members of less area than the area exposed to external pressure.

'2. A piston comprising opposed spaced members relatively movable toward and away from each other and having a centrally disposed chamber and compressible cylindrical packing capable of flowing, between portions of the piston members, said packing being engaged by the portions of the piston members of less area than the area exposed to external pressure.

3. A piston comprising opposed spaced members having centrally reduced portions between which a chamber is formed, a plastic packing of cylindrical form disposed between the parts of the piston members beyond the said chamber, the packing being engaged by portions of the piston members of less area than the area exposed to external pressure.

4. A piston comprising opposed spaced members relatiye-ly movable toward and away from each'other, one of said members having a centrally disposed reduced portion and a plastic packing mounted upon the reduced portion of the piston and capable of flowing, the packing being engaged by portions of the piston members of less area than the area exposed to external pressure;

In testimony whereof I have hereunto set my hand at Paris (France), this 28th day of November, 1916.

A. LE BRUN.

In the presence of L. DE CAUDI, PICHCE DAE. 

